1. Field of the Invention
The present invention relates to an ink jet recording apparatus that conveys a recording medium for recording images on it by use of an ink jet method. The invention also relates to a recording method therefor.
2. Related Background Art
An ink jet recording apparatus forms droplets of ink by various methods and discharges them onto a recording medium, such as recording paper, for recording by the adhesion of the ink droplets to the recording medium. Particularly, the ink jet recording apparatus that utilizes heat as energy for forming the discharge droplets makes it easier to arrange a plurality of discharge ports (nozzles) in high density. Then, with the nozzles thus arranged in high density, the ink jet recording apparatus can provide high quality images in high resolution at high speeds to make it easier to form color images. These are excellent features. Since the ink jet recording apparatus discharges ink onto a recording medium in accordance with a recording signal, it is used widely as a quiet recording method which is applicable at lower running costs.
Now, with the ink jet recording apparatus thus structured, it may be desired to perform recording on the entire recording area (recording without any margins) on a recording medium in order to obtain an image recorded in the same size as that of the recording medium. However, when operating such an entire area recording, it is required to provide highly precise positioning with respect to the relative relations between the recording medium and the ink jet recording head. Actually, therefore, the positional deviation may take place between the recorded image and the recording medium so that a small amount of ink is discharged outside the recording medium, and the platen of the apparatus is stained. Moreover, in some cases, a margin may be produced on the recording medium to the extent that ink is discharged onto the platen. In order to prevent the creation of such a margin on a recording medium due to the errors existing in the relative positions between the recording medium and the ink jet recording head, it may be possible to record an image in a size larger than that of the recording medium. In this case, however, a problem is encountered that the amount of ink that may be discharged outside the recording medium becomes greater to eventually stain the platen. If the platen is stained by ink, there occurs such trouble that the front side or the reverse side of the recording medium carried to the position of the platen is stained by ink that has adhered to the platen, and the recording medium on which images are recorded is made worthless.
Further, if recording is performed on a recording medium which has been carried obliquely a large amount of ink is discharged on the platen, and not onto the recording medium eventually. Then, the recording apparatus itself may be damaged. Furthermore, when recording should be made on the trailing edge of the recording medium, it is required to continuously record on the recording medium even after the recording medium has passed the conveying roller which is positioned on the entrance side of the recording unit. However, while the recording medium is being conveyed in this manner, errors tend to take place in the conveying amount of the recording medium due to the kicking out thereof by the conveying roller on the entrance side at the moment the recording medium passes over the position of the conveying roller on that side (that is, the moment the trailing edge of the recording medium has passed through the roller on the entrance side). As a result, a problem is encountered that a margin is created inevitably between the image recorded by the scanning of the recording head before the kick-out of the recording medium and the one recorded by the scanning of the recording head after the kick-out of the recording medium.